Add script handling on modem detection

[Aleksander Morgado]

> >> I am using the modemmanager on openwrt (master).
> >> While playing around, I noticed that it might be useful to trigger
> >> an event after the modemmanager has detected a modem.
> >> We already use '/usr/lib/ModemManager/connection.d' one a successful
> >> connection.
> >
> >
> > There's already such interface, but it is not one provided by
> > ModemManager, but ModemManager re-uses one from Freedesktop. You can
> > watch for new modems by using the Freedesktop ObjectManager:
> >
> > https://www.freedesktop.org/software/ModemManager/api/latest/ref-dbus-standard-interfaces-objectmanager.html
> >
>
>
> Thanks for the hint. I'll have a look at it right away.
>

I believe Florian is asking for a "dispatcher script" to be called
once we detect a new modem and before MM probes it, right? similar to
e.g. the dispatcher scripts we run when a bearer gets connected. I may
be mistaken though

-- 
Aleksander